1. Field of the Invention
The present invention relates to a liquid crystal display device and a testing method thereof, and more particularly, to a liquid crystal display device and a testing method thereof, which is suitable for improving reliability on testing process.
2. Discussion of the Related Art
In general, a liquid crystal display device displays desired images by controlling light transmittance in liquid crystal cells arranged in a matrix configuration on a liquid crystal display panel according to a video signal.
The liquid crystal display panel is comprised of a thin film transistor substrate, a color filter substrate, and a liquid crystal layer, wherein the two substrates are bonded to each other by a sealant in state of providing the liquid crystal layer interposed therebetween.
The color filter substrate is provided with a color filter array on an upper substrate, wherein the color filter array includes a black matrix to prevent light leakage; a color filter to realize color images; a common electrode to form a vertical electric field with pixel electrode; and an upper alignment film coated thereon so as to align liquid crystal molecules. Also, the thin film transistor substrate is provided with a thin film transistor array on a lower substrate, wherein the thin film transistor array includes a plurality of gate lines; a plurality of data lines, each data line crossing each gate line; a plurality of thin film transistors TFTs, each thin film transistor TFT formed adjacent to each crossing portion of the gate and data lines; a pixel electrode connected to the thin film transistor TFT; and a lower alignment film coated thereon so as to align the liquid crystal molecules.
The method of fabricating the liquid crystal display panel includes a patterning process for forming the thin film transistor array and the color filter array; a bonding process for bonding the thin film transistor substrate and the color filter substrate to each other in state of providing the liquid crystal layer therebetween; and a testing process for detecting the defective liquid crystal display panel.
Through the testing process, it is tested whether the liquid crystal display panel is defective or not before a drive integrated circuit is adhered to the liquid crystal display panel. In more particular, the liquid crystal display panel is loaded to a testing apparatus which is maintained under the circumstances identical to those for a liquid crystal display module of finished product into which a backlight unit and drive integrated circuit are assembled. After loading the liquid crystal display device to the testing apparatus, a test signal which is identical to a driving signal applied when driving the liquid crystal display module is applied to the liquid crystal display panel, whereby the image is displayed on the liquid crystal display panel. At this time, if there is a defective signal line in the liquid crystal display panel being loaded to the testing apparatus, the pixel connected to the defective signal line displays the different image from that of the pixel connected to the normal signal line. Accordingly, a worker can recognize the defectiveness in the liquid crystal display panel.
To supply the test signal to the signal line on the testing process, signal pads connected to the signal lines are respectively connected to the probe pin by one-to-one correspondence. However, since the signal pads are increased in number due to the large-sized liquid crystal display panel, particles may occur, the probe pin may be damaged, or the misalignment may occur between the signal pads and the probe pin.